The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
An exhaust system includes a catalytic converter and oxygen (O2) sensors. A pre-converter O2 sensor measures O2 entering the catalytic converter. A post-converter O2 sensor measures the O2 exiting the catalytic converter. The O2 sensors may be diagnosed to determine whether the measurements taken are reliable.
The post-converter O2 sensor generates a voltage output signal based on sensor measurements. For example, a properly functioning post-converter O2 sensor may have a relatively quick response to changing levels of O2. Conversely, a malfunctioning post-converter O2 sensor may have a relatively slow response. Diagnosing the post-converter O2 sensor may include monitoring the voltage output signal and determining whether a response time is above and/or below a threshold.